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Search Results: 1 - 10 of 106521 matches for " ZHANG QUN "
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Phase locking of two independent degenerate coherent anti-Stokes Raman scattering processes
Qun Zhang
Physics , 2008,
Abstract: We propose an elegant scheme towards phase locking of two independent degenerate coherent anti-Stokes Raman scattering (CARS) processes. The optical implementation involves a modified Mach-Zehnder interferometer that is utilized to transfer phase coherence from three totally uncorrelated laser beams into two degenerate CARS beams which are independently produced in two distinct Raman active samples. Such a phase-transport interferometer allows for explicit measurement and control of phase differences between the two phase-locked degenerate CARS processes, hence may lead to applications in other pertinent research fields.
Performance Research of Private Investment—Case Study of Nanjing  [PDF]
Jianfei Leng, Qun Zhang, Pei Tang
American Journal of Industrial and Business Management (AJIBM) , 2014, DOI: 10.4236/ajibm.2014.410066
Abstract:

This paper analyzes the function of the transportation, energy supply, water supply, telecommunications, environmental protection and other infrastructure factors on private investment, and takes the city of Nanjing as an example for the empirical analysis. Based on data from 1992 to 2011 for factor analysis, we conclude that infrastructure has promoted to private investment and that the level of infrastructure has become the bottleneck of economic development. For this reason, we should continue to improve its quantity and quality

Performance Evaluation and Optimization of Math-Similarity Search
Qun Zhang,Abdou Youssef
Computer Science , 2015,
Abstract: Similarity search in math is to find mathematical expressions that are similar to a user's query. We conceptualized the similarity factors between mathematical expressions, and proposed an approach to math similarity search (MSS) by defining metrics based on those similarity factors [11]. Our preliminary implementation indicated the advantage of MSS compared to non-similarity based search. In order to more effectively and efficiently search similar math expressions, MSS is further optimized. This paper focuses on performance evaluation and optimization of MSS. Our results show that the proposed optimization process significantly improved the performance of MSS with respect to both relevance ranking and recall.
A Novel Scheme with Adaptive Sampling for Better Spectrum Utilization in Cognitive Radios  [PDF]
Qun PAN, Xin ZHANG, Ruiming ZHENG, Yongyu CHANG, Dacheng YANG
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.11007
Abstract: In cognitive radio (CR) networks, cognitive users need continuously monitor spectrum to decrease or avoid interference to primary users, yet attain a reasonable throughput. In this paper, we exploit a scheme to dynamically change the detection time duration to gain maximum throughput. Meanwhile the average de-tection time is kept as small as possible. The advantages of our approaches are approved by the deductions. Also the simulation results enable us to recognize the improved performance of our scheme over those ones with fixed detection time assignment.
Wavelet chaotic neural networks and their application to continuous function optimization  [PDF]
Jia-Hai Zhang, Yao-Qun Xu
Natural Science (NS) , 2009, DOI: 10.4236/ns.2009.13027
Abstract: Neural networks have been shown to be pow-erful tools for solving optimization problems. In this paper, we first retrospect Chen’s chaotic neural network and then propose several novel chaotic neural networks. Second, we plot the figures of the state bifurcation and the time evolution of most positive Lyapunov exponent. Third, we apply all of them to search global minima of continuous functions, and respec-tively plot their time evolution figures of most positive Lyapunov exponent and energy func-tion. At last, we make an analysis of the per-formance of these chaotic neural networks.
A Novel Frequency Selective Surface with Improved Miniaturization Performance  [PDF]
Wanlu Li, Tong Zhang, Guohui Yang, Qun Wu
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.43014
Abstract: Based on previous work, a novel Frequency Selective Surface (FSS) consisting of two metallic layers is proposed. The first layer is inductive-designed to generate the band-pass performance, while the second layer is capacitive-designed so that the miniaturization characteristic can be further improved. As a result, compared with the traditional single-layer structure, the profile of the FSS proposed is relatively small with the cell’s dimension only 0.0814λ × 0.0814λ. Moreover, the structure’s stability corresponding to waves of different polarizations and incident angles are also testified, which ensures the practicability of the proposed structure.
Case Analysis of the ZC Company’s AS Power Project Investment Decision-Making  [PDF]
Jian-Fei Leng, Qun Zhang, Xiang-Nan Wang
American Journal of Industrial and Business Management (AJIBM) , 2015, DOI: 10.4236/ajibm.2015.511064
Abstract: First, combined with relevant theories of modern investment decision-making, this paper took AS power engineering project of ZC Company for instance, analyzed objective function of power engineering investment structure in ZC Company. Second, this paper analyzed investment decision-making structure of AS power engineering project in ZC Company, and obtained specific results of investment decision-making, and the related results were verified. Through analysis and exploration, this paper has a scientific impact on ZC Company for the AS power project investment, while it’s hoped that it can play a role in electric power engineering projects of other companies in China. So it can better promote the development of electrical engineering investment in electrical industry.
Taichi Softball as a Novel Chinese Health-Promoting Exercise for Physical Health: A Systematic Review and Meta-Analysis  [PDF]
Liye Zou, Huiru Wang, Mark Zhang, Zhongjun Xiao, Qun Fang
Open Journal of Preventive Medicine (OJPM) , 2017, DOI: 10.4236/ojpm.2017.72002
Abstract: Background: Taichi softball was voted as one of the most popular health-promoting exercises in the category of ball games, which is attributed to that Taichi softball is not only beneficial for lower extremity-related physical health (e.g., balance, leg strength, and flexibility), but can also develop manipulative skill and hand-eye coordination (eating, bathing, dressing, bathing required manipulative skills, grips movement and strength). However, the positive effects of Taichi softball on physical health have rarely been investigated. Therefore, the purpose of this systematic review was to evaluate the effect of Taichi softball on physical health. Methods: Five electronic databases were used to conduct literature searches. Two review authors independently extracted data in a standardized manner. The methodological quality of studies included was independently evaluated according to the Cochrane Collaboration’s for Assessing Risk of Bias from the Cochrane Handbook for Systematic Review Interventions. The standard mean difference (SMD) and 95% confidence interval (CI) using more conservative random effects model were calculated. Results: The sample size of 411 participants ranged from 32 to 150 in the RCTs, along with a wide age range from 18 to 75. The length of Taichi softball intervention peri-ods in the eligible studies ranged from 12 weeks to 12 months. The participants in the studies consisted of healthy college students, patients with Type 2 diabe-tes, and older adults from community centers. Six randomized controlled trials were used for the meta-analysis. The aggregated results are in favor of Taichi softball on improving physical health in participants with healthy status and Type 2 Diabetes Mellitus. The improvement on the primary components of the physical health consisted of handgrip strength (SMD, -0.6, 95% CI -0.84 to 0.36, p < 0.00001), trunk flexibility (SMD, -0.4, 95% CI -0.74 to -0.05, p = 0.03), static (SMD, -0.73, 95% CI -0.94 to -0.51, p < 0.00001) and dynamic balance (SMD, -0.68, 95% CI -1.2 to -0.17, p = 0.009). Conclusions: Taichi softball appears to be beneficial for improving physical health (hand strength, physical balance, flexibility, aerobic endurance, resting heart rate, diastolic and systolic pressures) among healthy adults and patients with Type 2 Diabetes. However, because of the low methodological quality of assessment, ill-designed experimental designs, and small study size, a definite conclusion of Taichi softball improving physical health can be confirmed along with high-quality studies with long follow-up.
In situ accurate determination of the zero time delay between two independent ultrashort laser pulses by observing the oscillation of an atomic excited wave packet
Qun Zhang,John W. Hepburn
Physics , 2008, DOI: 10.1364/OL.33.001893
Abstract: We propose a novel method that uses the oscillation of an atomic excited wave packet observed through a pump-probe technique to accurately determine the zero time delay between a pair of ultrashort laser pulses. This physically-based approach provides an easy fix for the intractable problem of synchronizing two different femtosecond laser pulses in a practical experimental environment, especially where an in situ time zero measurement with high accuracy is required.
Evaluation Procedure for Quality Consistency of Generic Nifedipine Extended-Release Tablets Based on the Impurity Profile  [PDF]
Ming-Yuan Zhang, Jun-Dong Zhang, Qun Gao, Yan Liu, Feng Lu
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.69074
Abstract: A procedure to evaluate the quality consistency of generic drugs based on the impurity profile and the similarity analysis methods was presented in this paper. Nifedipine extended-release tablets from six generic factories of China were used to evaluate the uniformity with the original drug in the study. The procedure includes: choice of chromatographic methods, data collection and conformity test, evaluation of intra-batch similarity of drugs, evaluation of generic drugs with the original drug and weighted similarity evaluation of generic drugs. The data were collected via high-performance liquid chromatography (HPLC), and then calculated by correlation coefficient, cosine, principal component analysis (PCA) and hierarchical clustering analysis (HCA). It is more suitable to use peak areas as the vector when calculating the similarity of impurity profile. After weighting the peak areas of the unspecified impurities in further evaluation of the generic quality, the generic level of different factories was differentiated and the best generic factory was picked out.
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